A captured image format. If true, it returns a PNM image. Otherwise, it returns pixel data only in BGR or gray-scale format.

copy

A memory allocation scheme. If true, the function allocate a new memory block to store an image. A user is responsible for releasing the memory block later. Otherwise, it returns an internal memory block, which is not suppposed to be freed by a user.

This is the color depth of final (possibly converted) images. If a user requests a gray-scale image and the capture device supports only a color image, then a captured color image is converted internally into a gray-scale image. In this case, the return value of the function is 1, not 3.